Drywall joint tape and method

ABSTRACT

A joint tape for drywall includes a substrate layer having an elongate shape in a lengthwise direction and being flexible in the lengthwise direction and in a transverse direction. The tape further includes a covering layer disposed in bonding relation on the substrate layer. The covering layer is rigid in the transverse direction and configured to withstand compressive forces applied generally in the transverse direction and shear stresses applied generally along the transverse direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

The instant application claims the benefit of the filing date of U.S.Provisional Application No. 61/885,881, filed on Oct. 2, 2013, thecontents of which are hereby incorporated herein in their entirety bythis reference.

BACKGROUND

Typical load bearing or separation wall assemblies in buildings are madeof support structures, for example, wooden or metal studs, covered bywallboards. There are many different types of wallboard for usedepending on the requirements of various applications. One wallboardtype that is most commonly used to build internal walls in buildings isgypsum wallboard, which is conventionally attached to studs. Gypsumwallboards are available in various standard sizes having predeterminedwidth, for example, 4 ft., and predetermined lengths such as 8 ft., 10ft., or other sizes. In conventional installations, wallboards areassembled end-to-end and/or side-to-side to cover wall surfaces greaterthan the length or width of the drywall sheets, which requires jointsalong edges of wallboard sheets to be created.

Typical wallboard joints are constructed by a combination of a jointcompound and a matrix material to create a composite structure lendingstrength to the joint. Similar processes are also used to make wallboardrepairs and/or finish inside and outside wall corners. One matrixmaterial commonly used for wallboard joints is a rolled material,commonly referred to as “tape.” When constructing a joint, a layer ofjoint compound may be laid along a joint before a layer of tape is addedalong and covering the joint. One or more layer of joint compound may beadded over the tape, and over each other, as is known. The resultinglayers of dried joint compound and tape make up a composite jointstructure that should be able to withstand various stresses such astensile, compressive and shear stresses that may be present at thejoint, such that cracks and breaks are avoided as wall structures mayshift, settle or otherwise become stressed. However, this is not thecase. Although composite joint structures are generally effective inwithstanding tensile stresses, i.e., stresses tending to pull the jointapart, they are not sufficiently resilient against compressive or shearstresses tending to compress or slide the joint.

There are two conventional types of tape used in the art today. Thefirst type, made of paper, includes a continuous or perforated tapestrip that offers little to no strength in the compressive direction.The second type, made of fiberglass, is also weak in a compressivestress direction. In general, fiberglass tape is not ideal forstabilizing joints between drywall boards because, while it hascross-directional fibers (short fibers whose length is the width of thetape) that are strong in tension and provide excellent resistance totensile forces pulling the joint apart, it provides almost no resistanceto compressive forces that push the boards closer together. Numerousdrywall joint strength tests have shown that fiberglass mesh tape makesa joint relatively strong when tensile forces are placed on the joint,but when compressive or shearing forces are placed on the joint, itfails easily. Joint failure manifests itself as joint compound cracking,which requires repair. For this reason, fiberglass joint tape is notrecommended for use with drying type joint compounds, which are not asstrong and crack-resistant as setting-type compounds.

Samples of a drywall joint made with Fibatape® tape have been tensiletested in accordance with ASTM C 474 (Appendix) which measures thestrength to first crack of a tape-compound sample coated in electricallyconductive paint. The strength is measured until the first crack in thepaint occurs, which breaks the electrical continuity along the surfaceand registers the ultimate tensile load. Such failures suggest thattypical taped joints do not optimize the strength of the glass-jointcompound composite. In one mode of failure, tensile loads tend toseparate the glass fibers from the joint compound matrix instead oftransferring these loads to the glass fibers themselves.

SUMMARY

In one aspect, the disclosure describes joint tape for drywallapplications. The joint tape includes a substrate layer having anelongate shape in a lengthwise direction and being flexible in thelengthwise direction and in a transverse direction. The tape furtherincludes a covering layer disposed in bonding relation on the substratelayer. The covering layer is rigid in the transverse direction andconfigured to withstand compressive forces applied generally in thetransverse direction and shear stresses applied generally along thetransverse direction.

In another aspect, the disclosure describes a drywall joint between twoadjacent drywall panels. The joint includes a layer of joint compounddisposed along generally abutting edges of the two adjacent drywallpanels, and a joint tape embedded within the layer of joint compound.The joint tape includes a substrate layer having an elongate shape in alengthwise direction along the generally abutting edges. The substratelayer is flexible in the lengthwise direction and in a transversedirection, which is perpendicular to the lengthwise direction. The jointtape further includes a covering layer disposed in bonding relation onthe substrate layer. The covering layer is rigid in the transversedirection and configured to withstand compressive forces appliedgenerally in the transverse direction tending to push the two adjacentdrywall panels towards each other, and shear stresses applied generallyalong the transverse direction tending to slide the two drywall panelsrelative to one another along the abutting edges thereof.

In yet another aspect, the disclosure describes a method formanufacturing joint tape for use in drywall joints. The method includesproviding a substrate layer that is flexible in a lengthwise directionand in a transverse direction. The method further includes providing acovering layer that is flexible in the lengthwise direction but is rigidin the transverse direction. When manufacturing the joint tape, thesubstrate and covering layers are deposited in overlapping relation tocreate a joint tape preform. The substrate layer is then bonded to thecovering layer in the joint tape preform to create a joint tape that isflexible in the lengthwise direction but rigid in the transversedirection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross section of a wall board joint in accordancewith the disclosure.

FIG. 2 illustrates a roll of joint tape in accordance with thedisclosure.

FIGS. 3-6 illustrate various embodiments of joint tape in accordancewith the disclosure.

FIG. 7 illustrates a cross section of one embodiment for a joint tape inaccordance with the disclosure.

FIG. 8 illustrates an alternative embodiment for a joint tape inaccordance with the disclosure.

FIG. 9 illustrates a manufacturing method for a joint tape in accordancewith the disclosure.

DETAILED DESCRIPTION

The present disclosure is applicable to drywall or other wallboardjoints and, more particularly, to a joint tape for use in compositejoint structures including the tape embedded into one or more type ofjoint compound. Various embodiments are described herein relative tojoint tape for drywall, but it should be appreciated that the structuresand methods relative to making or using joint tape are applicable toother types of wall panels as well.

A cross section of a drywall joint 100 is shown in FIG. 1. The drywalljoint 100. as shown, is a composite joint formed between two drywallpanels 102. Each panel forms a recessed section 104 along a joint edge106 to accommodate the materials making up the joint 100 such that aflat surface is presented on an external drywall surface 108. The joint100 is referred to herein as a “composite” joint, which means that thejoint structure is made of the combination of different materials. Forexample, the joint 100 in the illustrated embodiment includesoverlapping layers of hardened joint compound 110, a joint tape 112embedded within the hardened joint compound 110, and an optionalskim-coat compound layer 114, which is formable to a fine finish surfacemade to match the external drywall surface 108. Advantageously, thehardened joint compound 110 may be a drying type joint compound that,when embedding the tape 112, forms a structure having superiorresistance to compressive and shear stresses that was previouslyachieved. The tape 112, although shown embedded in the joint compound,may alternatively include a layer of adhesive affixing it directly ontothe drywall before deposition of the joint compound. As is known, jointsbetween various wall panels may be assembled in stages, which includematerial deposition, forming and sanding between each application. Inthe illustrated embodiment, the joint tape 112 is advantageouslyconfigured to withstand shear, tensile and compressive stresses appliedbetween the two wall panels 102.

A roll of joint tape 200 is shown in FIG. 2 to illustrate variousstructural and/or functional aspects thereof. The roll 200 may be madeup of the same or a similar type of joint tape 112, as shown anddescribed in FIG. 1. The roll of joint tape 200 is advantageouslyconfigured for dispensing appropriate lengths of tape 202 duringassembly of drywall joints. As can be seen in FIG. 2, the tape 202 ismade of two layers—a substrate layer 204 and a covering layer 208. Asused herein, “layer” denotes a plurality or group of fibers that sharesimilar traits including but not limited to a similar composition, size,function, and/or deposition pattern, but not necessarily a particularpositioning in the tape structure. Therefore, while the two separatesubstrate and covering layers are described and shown in accordance witha handful of embodiments for joint tape, it is contemplated that thevarious fibers that make up these layers can be woven together. In otherwords, while the layers are shown and described separately in certainembodiments, the substrate and covering layers may be woven together ina single fabric.

In the illustrated embodiment, the substrate layer 204 forms thesubstrate of the tape 202, has a generally elongate shape extendingalong a major axis of the tape 202, and forms the material layer of thetape 202 that permits the rolling of the tape 202 into the roll 200,provides flexibility for application and handling of the tape 202, andthe like. In one embodiment, the substrate layer 204 may include anadhesive permitting its installation directly onto the drywall panelsaround a joint before the tape is embedded with joint compound. Thesubstrate layer 204 may be made of any appropriate material having goodflexing and strength properties permitting the formation of the tape 202in to the roll 200. Materials considered appropriate for forming thesubstrate layer 204 include reinforced plastic, glass, fabric or metal,each of which is formed into strings, threads or fibers 206 that arewoven or otherwise structured into an elongate shape. Depending on thematerial used to make them, the fibers of the substrate layer 204 havesufficient flexibility to allow handling, application and rolling of thetape because these fibers will extend in a lengthwise direction relativeto a seam between wall panels (along edges 106, as shown in FIG. 1) andare, thus, not expected to withstand considerable stresses afterformation of the joint 100.

The covering layer 208 of the tape 202 forms the portion of the jointstructure 100 (FIG. 1) that provides superior resistance to compressiveand shear stresses than previously proposed tape designs. In theillustrated embodiment, the covering layer 208 is made from a pluralityof transversely extending fibers 201, which possesses rigidity alongtheir respective axial direction such that, the entire tape assembly canresist compressive and shear stresses. For clarity, the lengthwisedirection of the tape is along the tape's rolling direction, which isillustrated with the designation “L” in FIG. 2, and the transversedirection is the direction perpendicular to the lengthwise direction,which is illustrated with the designation “W” in FIG. 2.

In the tape 202, the cross-fibers 210 in the covering layer 208 are madeof metal, glass, plastic or another suitable material that can be formedinto fibers and that possesses resistance to buckling under compressiveor shear stresses when integrated into a matrix of settable cementitiousmaterial such as set drywall joining compound. In one contemplatedembodiment, the fibers making up the substrate layer 204 have differentmechanical properties than the fibers making up the covering layer 208so that each layer can be tailored or configured to account forflexibility (substrate layer) and rigidity (covering layer). In oneembodiment, the fibers in the covering and substrate layers 204 and 208are woven together such that the tape is made up of a single fabriclayer. In other words, the tape 202 is advantageously flexible in thelengthwise direction, which allows the tape to be handled, installed andpackaged, and rigid in the cross-wise or transverse direction, whichenables to the joint 100 to withstand compressive and shear loading.

The desired difference in mechanical properties between the substrateand covering layers 204 and 208 can be accomplished by differentmethods. In one embodiment, the fibers between the two different layersmay be made of different materials, for example, flexible fabric orglass mat for the substrate layer 204 and rigid plastic for the coveringlayer 208. Alternatively, the fibers may be made of the same material,for example, glass, plastic or metal, but have different gauges orcross-sectional sizes, with thinner, more flexible fibers making up thesubstrate layer and thicker, more rigid fibers, making up the coveringlayer. Moreover, the pattern of fiber arrangement in either layer canalso help increase resistance to shear and compressive stresses.

Four different embodiments for the arrangement of fibers at least in thecovering layer for the tape 202 are shown in FIGS. 3-6. In theseembodiments, the bottom end of the tape is shown partially unraveled forillustration, and the substrate layer 204 is shown made up of the fibers206 extending parallel to one another for simplicity. It should beappreciated that in the tape embodiments shown in FIGS. 3-6, the fibersof the various substrate and covering layers are woven together into asingle fabric, which is shown from a top view for simplicity. In a firsttape embodiment 302, shown in FIG. 3, the covering layer 208 is made offibers 304 that extend parallel to one another in the transversedirection W. The covering layer fibers 304 are disposed at a spacing, d,from one another, which is selected based on the fiber width and thefiber material empirically to provide optimum compressive performancewhen embedded in a set cementitious joint compound material.

In a second tape embodiment 306, shown in FIG. 4, the covering layer 208is made of fibers 308 that extend at an angle, α, with respect to thetransverse direction W. In the illustrated embodiment, the angle α isabout 60°, but other angles may be used. The based on the fiber widthand the fiber material empirically to provide optimum compressiveperformance when embedded in a set cementitious joint compound material.

In a third tape embodiment 310, shown in FIG. 5, the covering layer 208is made of two different layers of fibers 312 arranged in a crisscrossconfiguration as shown. Specifically, a first network of fibers 312includes fibers that extend parallel to one another at a first angle,α1, and a second network of fibers 312 includes fibers that extendparallel to one another at a second angle, α2. To maintain symmetry andto permit installation of the tape in either direction, in theillustrated embodiment, α1=180°-α2. As shown, α1 is equal to about 60°,and α2 is equal to about 120°. In each of the first and second networksof fibers, the fibers 312 are disposed at a spacing, d, from oneanother, which is selected based on the fiber width and the fibermaterial empirically to provide optimum compressive performance whenembedded in a set cementitious joint compound material. As compared tothe tape 306, the tape 310 may be better equipped to handle shear andcompressive stresses owing to the increased covering layer fiberdensity, and to the angled disposition of the covering layer fibers intwo directions, which can withstand non-transversely applied compressivestresses.

In a fourth tape embodiment 314, shown in FIG. 6, the covering layer 208is made of three different layers of fibers 312 arranged in a crisscrossand in a transverse configuration as shown. Specifically, a firstnetwork of fibers 316 includes fibers that extend parallel to oneanother at a first angle, α1, a second network of fibers 316 includesfibers that extend parallel to one another at a second angle, α2, and athird network of fibers 316 includes fibers that extend parallel to thetransverse direction W. To maintain symmetry and to permit installationof the tape in either direction, in the illustrated embodiment,α1=180°-α2. As shown, α1 is equal to about 60°, α2 is equal to about120°, and the third network of fibers is parallel to the transversedirection W, or, at an angle of 0°. In each of the first, second andthird networks of fibers, the fibers 316 are disposed at a spacing, d,from one another, which is selected based on the fiber width and thefiber material empirically to provide optimum compressive performancewhen embedded in a set cementitious joint compound material. As comparedto the tape 310, the tape 314 may be better equipped to handle shear andcompressive stresses owing to the increased covering layer fiberdensity, to the angled disposition of the covering layer fibers in twodirections, and to the additional fiber layer, which can togetherwithstand transversely and non-transversely applied compressivestresses.

To augment the rigidity of the tape 202, in certain embodiments, anadhesive structure or operation may be added to bond the substrate andcovering layers to one another so that a more rigid tape structure canbe created. Two possible embodiments are shown in the cross sections ofFIGS. 7 and 8. In these figures, where like reference numerals are usedto denote similar structures as previously described for simplicity,cross sections are taken from one exemplary tape embodiment, here, thetape 202 shown in FIG. 2. In each section, the substrate layer fibers206 are shown at the bottom of the illustration, and the covering layerfibers 210 are shown, in cross section, at the top of the illustration.

In the first illustration, an adhesive 402 is added at every or, atleast, at a majority of intersections between substrate and coveringfibers. The adhesive 402 bonds the two fibers to each other and is madefrom a very rigid material, for example, settable epoxy, that preventsthe covering layer fibers from flexing at least locally, thus increasingthe overall rigidity of the tape 202. In the second illustration, asshown in FIG. 8, the adhesive 402 is omitted in favor of a weldingoperation performed to fuse the substrate fibers to the covering layerfibers at the points of intersection 404 between the two fiberarrangements. Such fusing or welding may be accomplished by differentmethods and on different materials. For example, in embodiments whereboth the substrate and the covering layer fibers are made of plastic,the fusing operation between the fibers at each intersection 404 may beaccomplished by heating the tape to locally melt the fiber material soit can fuse, by ultrasonic welding operation, by exposure of thematerials to a solvent, and by other appropriate methods.

A block diagram schematically illustrating a joint tape manufacturingprocess 406 in accordance with the disclosure is shown in FIG. 9. In theillustrated embodiment, a first feed roll 408 containing a substratelayer preform 410 supplies the preform via auxiliary rollers 412 to alayering station 414. Simultaneously, a second feed roll 416 containinga covering layer preform 418 supplies the respective preform to thelayering station 414, where the two preforms meet to make up a jointtape preform 420. The joint tape preform 420 passes through a bondingstation 422, where the preforms are pressed together and, optionally,bonded, to create a tape 202 that is rolled into a joint tape roll 422.Additional optional operations such that the application of walladhesive and release paper on the back of the tape may also be carriedout but are not shown here for simplicity.

When assembling the tape 202, various considerations can be taken intoaccount. For example, the joint tape preform 420 may be formed as a mathaving a width equivalent to multiple joint tape widths, which is thencut into sections making up each desired joint tape roll package.Moreover, in one alternative embodiment, each of the substrate layer andcovering layer preforms may be manufactured on demand, for example, byplastic extrusion of fibers, instead of being preformed into fibers thatare then used to assemble the tape. The bonding station 422 may applypressure and/or adhesive to bond the substrate and covering tape layersto one another in one step or in multiple steps. Alternatively, thebonding station may include a pool or vat of adhesive through which thetape passes so that adhesive collects at the fiber intersection sitesand otherwise drains off the remaining tape structure. In embodimentswhere more than one fiber layer makes up the covering tape layer, asbetween the covering fiber layers, the fibers may be connected to eachother using adhesive or may alternatively be tangled or woven to eachother by mechanical means.

It will be appreciated that the foregoing description provides examplesof the disclosed system and technique. However, it is contemplated thatother implementations of the disclosure may differ in detail from theforegoing examples. All references to the disclosure or examples thereofare intended to reference the particular example being discussed at thatpoint and are not intended to imply any limitation as to the scope ofthe disclosure more generally. All language of distinction anddisparagement with respect to certain features is intended to indicate alack of preference for those features, but not to exclude such from thescope of the disclosure entirely unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context.

The following examples further illustrate the invention but, of course,should not be construed as in any way limiting its scope.

EXAMPLE 1

This Example illustrates the shear strength of conventional fiberglasstape containing additional rigid members, for example, metalreinforcements, which are found to enhanced rigidity in the transversedirection of a joint. Wallboard samples 1A and 1B were prepared bycutting 3″ by 8″ drywall panels and constructing a joint by aligning thelong dimensions of the panels in an offset manner, overlapping by fourinches.

A 50/50 mixture by mass of Hardman® Part A 8173 and Hardman ® Part B8173 adhesives was applied in a thin layer along the paper surface ofthe two panels' adjoining sides. Metal reinforcements were then equallyspaced perpendicular to the joint and connected the two panels. Themetal reinforcements were lightly pressed into the layer of adhesive andallowed to adhere to the board surface for 24 hours. A section ofSHEETROCK® Fiberglass Drywall Tape was adhered directly to the metalreinforcements and board along the joint. A thin layer of joint compound(SHEETROCK® All-Purpose Joint Compound, Ready-Mixed) was applied overthe adhered fiberglass mesh tape using 22-gauge guide bars placed threeinches apart. The 22-gauge coat was allowed to dry for 24 hours, and thejoint was filled using 16-guage guide bars to produce a 4″ by 3″ by.055″ layer of joint compound.

All measurements were made on an ATS Model contained in a controlledtemperature/humidity room held at 70° F./50% R.H. The prepared samplewas then mounted in the test fixture and the test was performed incompression mode. Results for the shear strengths are provided below inTable 1, where “Fiberglass” tape denotes SHEETROCK® Fiberglass DrywallTape that was installed using SHEETROCK® All-Purpose Joint Compound(Ready-Mixed) onto the samples, and “Paper” tape denotes SHEETROCK®Paper Tape that was installed using SHEETROCK® All-Purpose JointCompound (Ready-Mixed).

TABLE 1 Tape Shear Strength (lbs) Fiberglass* 60 Sample 1A 123.7 Sample1B 117.3 Paper** 122

The use of the terms “a” and “an” and “the” and “at least one” andsimilar referents in the context of describing the invention (especiallyin the context of the following claims) are to be construed to coverboth the singular and the plural, unless otherwise indicated herein orclearly contradicted by context. The use of the term “at least one”followed by a list of one or more items (for example, “at least one of Aand B”) is to be construed to mean one item selected from the listeditems (A or B) or any combination of two or more of the listed items (Aand B), unless otherwise indicated herein or clearly contradicted bycontext.

Accordingly, this disclosure includes all modifications and equivalentsof the subject matter recited in the claims appended hereto as permittedby applicable law. Moreover, any combination of the above-describedelements in all possible variations thereof is encompassed by thedisclosure unless otherwise indicated herein or otherwise clearlycontradicted by context.

We claim:
 1. A joint tape for drywall, comprising: a substrate layerhaving an elongate shape in a lengthwise direction, the substrate layerbeing flexible in the lengthwise and in a transverse directions; and acovering layer disposed in bonding relation on the substrate layer, thecovering layer being rigid in the transverse direction and configured towithstand compressive forces applied generally in the transversedirection and shear stresses applied generally along the transversedirection.
 2. The joint tape of claim 1, wherein the substrate layer ismade of substrate fibers extending in the lengthwise direction.
 3. Thejoint tape of claim 1, wherein the covering layer is made of coveringfibers extending in the transverse direction.
 4. The joint tape of claim1, wherein the covering layer is made of covering fibers extending at anangle relative to the transverse direction.
 5. The joint tape of claim1, wherein the substrate and covering layers are woven together into asingle fabric layer.
 6. The joint tape of claim 1, wherein the substratelayer is made of substrate fibers and the covering layer is made ofcovering fibers, wherein the substrate and covering fibers intersect atintersection points, and wherein the joint tape further includes anadhesive disposed at each or at least at a majority of intersectionpoints to bond the substrate fibers to the covering fibers to oneanother.
 7. The joint tape of claim 1, wherein the substrate layer andthe covering layer are made from different materials.
 8. The joint tapeof claim 1, wherein substrate layer includes substrate fibers and thecovering layer includes covering fibers, wherein the substrate fibersare made of the same material as the covering fibers, and wherein thesubstrate fibers are thinner and more flexible than the covering fibers,which are thicker and more rigid.
 9. The joint tape of claim 8, whereinthe substrate layer is fused to the covering layer through a weldingoperation.
 10. A drywall joint between two adjacent drywall panels,comprising: a layer of joint compound disposed along generally abuttingedges of the two adjacent drywall panels; a joint tape embedded withinthe layer of joint compound, the joint tape comprising: a substratelayer having an elongate shape in a lengthwise direction along thegenerally abutting edges, the substrate layer being flexible in thelengthwise direction and in a transverse direction, which isperpendicular to the lengthwise direction; and a covering layer disposedin bonding relation on the substrate layer, the covering layer beingrigid in the transverse direction and configured to withstandcompressive forces applied generally in the transverse direction tendingto push the two adjacent drywall panels towards each other, and shearstresses applied generally along the transverse direction tending toslide the two drywall panels relative to one another along the abuttingedges thereof.
 11. The drywall joint of claim 10, wherein the substratelayer is made of substrate fibers extending in the lengthwise direction.12. The drywall joint of claim 10, wherein the covering layer is made ofcovering fibers extending in the transverse direction.
 13. The drywalljoint of claim 10, wherein the covering layer is made of covering fibersextending at an angle relative to the transverse direction.
 14. Thedrywall joint of claim 10, wherein the substrate and covering layers arewoven together into a single fabric layer.
 15. The drywall joint ofclaim 10, wherein the substrate layer is made of substrate fibers andthe covering layer is made of covering fibers, wherein the substrate andcovering fibers intersect at intersection points, and wherein the jointtape further includes an adhesive disposed at each or at least at amajority of intersection points to bond the substrate fibers to thecovering fibers to one another.
 16. The drywall joint of claim 10,wherein the substrate layer and the covering layer are made fromdifferent materials.
 17. The drywall joint of claim 10, whereinsubstrate layer includes substrate fibers and the covering layerincludes covering fibers, wherein the substrate fibers are made of thesame material as the covering fibers, and wherein the substrate fibersare thinner and more flexible than the covering fibers, which arethicker and more rigid.
 18. The drywall joint of claim 17, wherein thesubstrate layer is fused to the covering layer through a weldingoperation.
 19. A method for manufacturing joint tape for use in drywalljoints, comprising: providing a substrate layer that is flexible in alengthwise direction and in a transverse direction; providing a coveringlayer that is flexible in the lengthwise direction but is rigid in thetransverse direction; depositing the substrate and covering layers inoverlapping relation to create a joint tape preform; and bonding thesubstrate layer to the covering layer in the joint tape preform tocreate a joint tape that is flexible in the lengthwise direction butrigid in the transverse direction.
 20. The method of claim 19, whereinbonding the substrate and covering layers is accomplished by at leastone of use of adhesive and a welding or fusing operation.